Suburban questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70GMCer · 02-11-2006, 08:01 AM

Can I replace my 1970 leaf rear to a 1984 suburban leaf rear without any issues? Will everything be pretty much bolt up the same, except mine is a 12 bolt, and the burb is a 14 bolt, I think. Or, would the axles by themselves, be the same. Would the axles fit into the 12 bolt? Now that's assuming that I have the wider housing on mine. I'm thinking on changing to 5 bolt lug from 6 bolt, and if I can use the burb parts, I will. Next, can the gas tank from the burb fit between the frame in the back, like the blazers tanks do?

thanks, steve

70GMCer · 02-11-2006, 11:10 AM

All the "info giants" on here, and no one knows?

neonlarry · 02-11-2006, 12:01 PM

Since no one else will answer i'll give my opinion, no, no and no. I think the spring perches are in a different position, the 14 bolt won't go in the 12 bolt case and I don't think the gas tank will fit the frame rails.

ABHaulR · 02-11-2006, 01:01 PM

well its not a 14bolt. 14b have 8 lugs and are one ton and 3/4 ton rears. you mentioned that you were going to go from6 lug to 5 lug.
Dwayne

70GMCer · 02-11-2006, 01:18 PM

I'm talking about the whole leaf rear end assembly fitting onto my truck, or the axles fitting into my 12 bolt housing. The burb is 5 lug and my 70 is 6 lug setup.

I kinda figured the gas tank was a no go. Thought I'd ask though......

**Palf70Step** · 02-11-2006, 01:21 PM

The spring perches are different between your 70 and the 84. 70 was also a changeover year, so you axle could be about 1" narrower or the same width. If you change the perch mountings it would work. Swapping guts probably not.

Far as the gas tank, if your truck is a SWB, then it probably wount fit. I have seen some use the later mould burb tanks in LWB trucks. If it is the 40 gal tank, it may need massaged to clear the rear end. I have heard the 30(ish) gallon tank does OK in the LWB. Just get out your tape measure and see.

*FormerMember* · 02-11-2006, 01:27 PM

If it were a 1ton 14B then yes, the spring perches are in the right location.

Other than that, they're off by about 2" a side.

70GMCer · 02-11-2006, 02:08 PM

That's the info I wanted to hear. I knew the the insides of both rears are different & wouldn't be the same. I never asked that, just about mounting or axle change. I'll be measuring the tank and see.

**special-K** · 02-11-2006, 02:48 PM

There were 14-bolt semi-floating rears w/6-lugs.They came in the light 2500s`88-up.I`m not sure exactly what rears you have.You can measure overall width.6 and 5-lug axles in the 12-bolts are interchangeable when they are from the same width units.Some people redrill the 6-lug axle flanges for 5 0n 5".

70GMCer · 02-11-2006, 03:38 PM

I'm also wondering if the axle splines are the same for the 84 and the 70?

02-11-2006, 08:01 AM	#1
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Suburban questions Can I replace my 1970 leaf rear to a 1984 suburban leaf rear without any issues? Will everything be pretty much bolt up the same, except mine is a 12 bolt, and the burb is a 14 bolt, I think. Or, would the axles by themselves, be the same. Would the axles fit into the 12 bolt? Now that's assuming that I have the wider housing on mine. I'm thinking on changing to 5 bolt lug from 6 bolt, and if I can use the burb parts, I will. Next, can the gas tank from the burb fit between the frame in the back, like the blazers tanks do? thanks, steve __________________ 1997 GMC Sierra Ext 1965 Mustang

02-11-2006, 11:10 AM	#2
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Suburban questions All the "info giants" on here, and no one knows? __________________ 1997 GMC Sierra Ext 1965 Mustang

02-11-2006, 12:01 PM	#3
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,746	Re: Suburban questions Since no one else will answer i'll give my opinion, no, no and no. I think the spring perches are in a different position, the 14 bolt won't go in the 12 bolt case and I don't think the gas tank will fit the frame rails. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

02-11-2006, 01:01 PM	#4
ABHaulR Registered User Join Date: Jun 2003 Location: West Valley City, Ut Posts: 311	Re: Suburban questions well its not a 14bolt. 14b have 8 lugs and are one ton and 3/4 ton rears. you mentioned that you were going to go from6 lug to 5 lug. Dwayne __________________ 72' GMC Suburban 10 1/2" of Lift, 40" Tires! Waiting for restoration 67' Chevy, What to do??? And Bad Ass American Bulldogs!

02-11-2006, 01:18 PM	#5
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Suburban questions I'm talking about the whole leaf rear end assembly fitting onto my truck, or the axles fitting into my 12 bolt housing. The burb is 5 lug and my 70 is 6 lug setup. I kinda figured the gas tank was a no go. Thought I'd ask though...... __________________ 1997 GMC Sierra Ext 1965 Mustang

02-11-2006, 01:21 PM	#6
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,083	Re: Suburban questions The spring perches are different between your 70 and the 84. 70 was also a changeover year, so you axle could be about 1" narrower or the same width. If you change the perch mountings it would work. Swapping guts probably not. Far as the gas tank, if your truck is a SWB, then it probably wount fit. I have seen some use the later mould burb tanks in LWB trucks. If it is the 40 gal tank, it may need massaged to clear the rear end. I have heard the 30(ish) gallon tank does OK in the LWB. Just get out your tape measure and see. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

02-11-2006, 01:27 PM	#7
FormerMember Account Suspended Join Date: Feb 2004 Posts: 3,051	Re: Suburban questions If it were a 1ton 14B then yes, the spring perches are in the right location. Other than that, they're off by about 2" a side.

02-11-2006, 02:08 PM	#8
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Suburban questions That's the info I wanted to hear. I knew the the insides of both rears are different & wouldn't be the same. I never asked that, just about mounting or axle change. I'll be measuring the tank and see. __________________ 1997 GMC Sierra Ext 1965 Mustang

02-11-2006, 02:48 PM	#9
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: Suburban questions There were 14-bolt semi-floating rears w/6-lugs.They came in the light 2500s`88-up.I`m not sure exactly what rears you have.You can measure overall width.6 and 5-lug axles in the 12-bolts are interchangeable when they are from the same width units.Some people redrill the 6-lug axle flanges for 5 0n 5". __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

02-11-2006, 03:38 PM	#10
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Suburban questions I'm also wondering if the axle splines are the same for the 84 and the 70? __________________ 1997 GMC Sierra Ext 1965 Mustang

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